Connection structure between electric wire and terminal, connection method between electric wire and terminal, and terminal

ABSTRACT

A connection structure between an electric wire and a terminal has an electric wire including a core wire with strands, and a terminal including a bottom-plate portion and a pair of core-wire-crimping pieces, which protrude from both edges of the bottom-plate portion and each distal-end portion of the pair of core-wire-crimping pieces being divided into a plurality of portions, the terminal enclosing and holding the core wire by the bottom-plate portion and the pair of core-wire-crimping pieces. The pair of core-wire-crimping pieces extends in directions to approach each other at a proximal-end portion, is in contact with each other at an intermediate portion, and extends in directions to be separated from each other at the distal-end portion. At least one portion of the plurality of portions of each distal-end portion of the pair of core-wire-crimping pieces extend in a different direction from other portions of the distal-end portion.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the priority of Japanese Patent Application No.2017-123899, filed on Jun. 26, 2017, the entire content of which areincorporated herein by reference.

BACKGROUND Technical Field

The present invention relates to a connection structure between anelectric wire and a terminal, a connection method between an electricwire and a terminal, and a terminal used in the connection structure andconnection method.

Related Art

Conventionally, a connection structure 301 between an electric wire anda terminal as illustrated in FIGS. 14 to 16 is known.

In the connection structure 301 between the electric wire and theterminal, a core wire (conductor) 309 of an electric wire 307 is held bycrimping a core-wire-crimping portion 305 of a terminal 303.

Here, JP 2005-116241 A can be listed as a technical literature relatingto the related art.

SUMMARY

Meanwhile, there is a case where the number of the strands 311constituting the core wire 309 is large in the conventional connectionstructure 301 between the electric wire and the terminal.

When the number of the strands 311 is large, there are many strands 311that are not in direct contact with the terminal 303 (thecore-wire-crimping portion 305) as illustrated in FIG. 16 at the time ofcrimping the core-wire-crimping portion 305 to hold the core wire 309.Incidentally, in FIG. 16, the strands 311 with hatching are the strands311 that are in direct contact with the core-wire-crimping portion 305to be conducted. Then, the strands 311 without hatching in FIG. 16 arethe strands 311 that are not in direct contact with thecore-wire-crimping portion 305 and is conducted the core-wire-crimpingportion 305 via the strands 311 that are in direct contact with thecore-wire-crimping portion 305.

In this manner, when there are many strands 311 that are not in directcontact with the core-wire-crimping portion 305, an electric resistancebetween the strands 311 adjacent to each other becomes large due to theinfluence of an oxide film or the like formed on a surface of thestrands 311. That is, if there are many strands 311 that are not indirect contact with the core-wire-crimping portion 305, there is aproblem that an electrical resistance between the terminal 303 (thecore-wire-crimping portion 305) and the core wire 309 increases.

This problem becomes remarkable as the number of strands 311 increases,and also becomes remarkable as the strand 311 is made of aluminum or thelike which is likely to form the oxide film on the surface.

The present invention has been made in view of the above-describedproblem, and an object thereof is to provide a connection structurebetween an electric wire and a terminal, a connection method between anelectric wire and a terminal, and a terminal which are capable ofreducing an electric resistance between a core wire of the electric wireand the terminal.

A connection structure between an electric wire and a terminal accordingto first aspect of the present invention has an electric wire includinga core wire with a plurality of strands and a terminal including abottom-plate portion and a pair of core-wire-crimping pieces, whichprotrude from both edges of the bottom-plate portion and each distal-endportion of the pair of core-wire-crimping pieces being divided into aplurality of portions, the terminal enclosing and holding the core wireby the bottom-plate portion and the pair of core-wire-crimping pieces.The pair of core-wire-crimping pieces extend in directions to approacheach other at a proximal-end portion, are in contact with each other atan intermediate portion, and extend in directions to be separated fromeach other at the distal-end portion. At least one portion of theplurality of portions of each distal-end portion of the pair ofcore-wire-crimping pieces extend in a different direction from otherportions of the distal-end portion.

The distal-end portion of the core-wire-crimping piece of the terminalmay be formed with a plurality of convex portions provided at apredetermined interval in the longitudinal direction of the electricwire, or the distal-end portion of the core-wire-crimping piece may beformed with a plurality of portions delimited by a plurality of slitsprovided at a predetermined interval in the longitudinal direction ofthe electric wire.

A terminal according to second aspect of the present invention includesa bottom-plate portion, and a pair of core-wire-crimping piecesprotruding from both edges of the bottom-plate portion. At least a partof each distal-end portion of the pair of core-wire-crimping pieces arebent in directions to approach each other.

A terminal according to third aspect of the present invention includes abottom-plate portion, and a pair of core-wire-crimping pieces protrudingfrom both edges of the bottom-plate portion and having distal-endportions divided into a plurality of portions. At least one portion ofthe plurality of portions of each distal-end portion of the pair ofcore-wire-crimping pieces extend in a different direction from otherportions of the distal-end portions.

A connection method for connecting an electric wire and a terminalaccording to fourth aspect of the present invention includes removing asheath at a part of an electric wire that includes a core wire with aplurality of strands and a sheath covering the core wire. The core wireexposed by removing the sheath are installed onto a core-wire-crimpingportion that includes a bottom-plate portion and a pair ofcore-wire-crimping pieces protruding from both edges of the bottom-plateportion and having distal-end portions divided into a plurality ofportions such that at least one portion of the plurality of portions ofeach distal-end portion extend in a different direction from otherportions of the distal-end portion. The core wire is enclosed and heldby the bottom-plate portion and the pair of core-wire-crimping piecessuch that the pair of core-wire-crimping pieces extend in directions toapproach each other at a proximal-end portion, are in contact with eachother at an intermediate portion, and extend in directions to beseparated from each other at the distal-end portion, and at least oneportion of the plurality of portions of each distal-end portion extendin the different direction from the other portions of the distal-endportion, after installing the core wire on the core-wire-crimpingportion.

A connection structure between an electric wire and a terminal accordingto fifth aspect of the present invention has an electric wire includinga core wire with a plurality of strands, a terminal including abottom-plate portion and a pair of core-wire-crimping pieces, whichprotrude from both edges of the bottom-plate portion and each distal-endportion of the pair of core-wire-crimping pieces being formed with aplurality of convex portions, the terminal enclosing and holding thecore wire by the bottom-plate portion and the pair of core-wire-crimpingpieces. The pair of core-wire-crimping pieces extends in directions toapproach each other at a proximal-end portion and is in contact witheach other at an intermediate portion, and the respective convexportions of the distal-end portion extend in directions to be separatedfrom each other.

The aspects of the present invention provides a connection structurebetween an electric wire and a terminal, a connection method between anelectric wire and a terminal, and a terminal which are capable ofreducing an electric resistance between a core wire of the electric wireand the terminal.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a developed view of a terminal used in a connection structurebetween an electric wire and a terminal according to one embodiment ofthe present invention;

FIG. 2 is a perspective view of the terminal used in the connectionstructure between the electric wire and the terminal according to theembodiment of the present invention, the view showing a state before theterminal is installed to the electric wire;

FIG. 3 is a cross-sectional view cut along III-III of FIG. 2;

FIG. 4 is a perspective view showing the connection structure betweenthe electric wire and the terminal according to the embodiment of thepresent invention;

FIG. 5 is a side view showing the connection structure between theelectric wire and the terminal according to the embodiment of thepresent invention;

FIG. 6 is a cross-sectional view cut along VI-VI of FIG. 5;

FIG. 7 is a cross-sectional view cut along VII-VII of FIG. 5;

FIG. 8 is a view in which broken lines indicating the distal-end portionof the cored wire crimping piece shown in FIG. 6 are added to FIG. 7;

FIG. 9 is a developed view of a terminal according to a variation, theview that corresponds to FIG. 1;

FIG. 10 is view of a terminal according to the variation, the view thatcorresponds to FIG. 3;

FIG. 11 is a developed view of a terminal according to anothervariation, the view that corresponds to FIG. 1;

FIG. 12 is a perspective view of a terminal used in a connectionstructure between an electric wire and a terminal according to stillanother variation, the view showing a state before the terminal isinstalled to the electric wire;

FIG. 13 is a cross-sectional view cut along XIII-XIII of FIG. 12;

FIG. 14 is a perspective view of a state before the terminal isinstalled to the electric wire in a conventional connection structurebetween an electric wire and a terminal;

FIG. 15 is a perspective view showing the conventional connectionstructure between the electric wire and the terminal; and

FIG. 16 is a cross-sectional view cut along XVI-XVI of FIG. 15.

DETAILED DESCRIPTION

In the following detailed description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the disclosed embodiments. It will be apparent,however, that one or more embodiments may be practiced without thesespecific details. In other instances, well-known structures and devicesare schematically shown in order to simplify the drawing.

Description will be hereinbelow provided for embodiments of the presentinvention by referring to the drawings. It should be noted that the sameor similar parts and components throughout the drawings will be denotedby the same or similar reference signs, and that descriptions for suchparts and components will be omitted or simplified. In addition, itshould be noted that the drawings are schematic and therefore differentfrom the actual ones.

As illustrated in FIGS. 4 and 5, a connection structure(electric-wire-terminal-connection structure) 1 between an electric wireand a terminal according to an embodiment of the present invention isconfigured to include an electric wire 3, a terminal (crimp terminal) 5installed on the electric wire 3. For example, a mating terminal (notillustrated) on which another electric wire (not illustrated) isinstalled is connected to the terminal 5 used in theelectric-wire-terminal-connection structure 1.

For convenience of description, the longitudinal direction of theelectric wire 3 and the terminal 5 in theelectric-wire-terminal-connection structure 1 is defined as thefront-rear direction FR, a predetermined direction orthogonal to thefront-rear direction FR is defined as the width direction WD, and adirection orthogonal to the front-rear direction FR and the widthdirection WD is defined as the vertical direction VT (height direction).Moreover, with respect to the vertical direction VT specified in FIG. 3and the like, the side on which a bottom-plate portion 17, to bedescribed later, is disposed is referred to as the lower side LOW, andthe side on which core-wire-crimping pieces 19, to be described later,are disposed is referred to as the upper side UP.

In addition, when a plane that passes through the center of theelectric-wire-terminal-connection structure 1 and is orthogonal to thewidth direction WD is assumed as a central plane, the electric wire 3and the terminal 5 of the electric-wire-terminal-connection structure 1are formed to be symmetric with respect to this central plane, that is,to be bilaterally symmetric.

The electric wire 3 is configured to include a core wire (conductor) 7and a sheath (sheath having insulation properties) 9 covering the corewire 7. The core wire 7 is constituted by a plurality of strands 11. Thestrand 11 is formed to be elongated, for example, in a columnar shapeusing metal such as aluminum and copper or an alloy thereof.

In the electric wire 3, a part (for example, one end in the longitudinaldirection; a front end in the front-rear direction FR) of the sheath 9is removed to expose the core wire 7.

The plurality of strands 11 are collected in a bundle in the form ofbeing twisted or being linearly extended and bundled, therebyconstituting the core wire 7. The core wire 7 (the electric wire 3) hasflexibility. A cross section (a cross section taken along a planeorthogonal to the longitudinal direction) of a portion of the electricwire 3 from which the sheath 9 has not been removed is, for example, acircular shape.

More specifically, the cross section of the core wire 7 formed bygathering the strands 11 substantially without gaps is formed in asubstantially circular shape. The sheath 9 covering the core wire 7 witha predetermined thickness is formed in an annular shape having apredetermined width and the entire outer circumference of the circularcore wire 7 is in contact with the entire inner circular circumferenceof the sheath 9. In addition, in the state of only the electric wire 3on which the terminal 5 or the like is not installed, the strands 11adjacent to each other are not fixed but are in a state of being just incontact with each other.

The terminal 5 is formed, for example, by forming a flat plate-shapedmetallic material into a predetermined shape (see FIG. 1) andappropriately bending the material into this predetermined shape (seeFIG. 2). In addition, the terminal 5 is configured to include acore-wire-crimping portion (a core wire connecting portion; a core wireinstalling portion) 13, a sheath-crimping portion (sheath installingportion) 15, and a mating terminal connecting portion (not illustrated).In the terminal 5, the mating terminal connecting portion, thecore-wire-crimping portion 13, and the sheath-crimping portion 15 arearranged in this order from the front side F to the rear side R in thefront-rear direction FR.

Furthermore, a first joining portion 27 is provided between the matingterminal connecting portion and the core-wire-crimping portion 13 asillustrated in FIG. 2 and the like. Further, a second joining portion 29is provided between the core-wire-crimping portion 13 and thesheath-crimping portion 15.

As illustrated in FIGS. 2 and 3, the core-wire-crimping portion 13 isconfigured to include the bottom-plate portion 17 and a pair ofcore-wire-crimping pieces 19 protruding from both edges of thebottom-plate portion 17. As illustrated in FIGS. 6 to 8, thecore-wire-crimping portion 13 encloses and holds the core wire 7 by thebottom-plate portion 17 and the pair of core-wire-crimping pieces 19 inthe crimped state of the pair of core-wire-crimping pieces 19 and thebottom-plate portion 17.

Each of the pair of core-wire-crimping pieces 19 is configured toinclude a distal-end portion (a portion distant from the bottom-plateportion 17) 21, a proximal-end portion (a portion on the bottom-plateportion 17) 23, and an intermediate portion (a portion between thedistal-end portion 21 and the proximal-end portion 23) 25. Thedistal-end portion 21 is divided into a plurality of portions 21A, 21B,and 21C in the front-rear direction FR (see FIGS. 1, 2, and the like)

Here, a state where the core-wire-crimping portion 13 holds the corewire 7 is assumed as a core-wire-holding state of core-wire-crimpingportion. As illustrated in FIGS. 6 to 8, the bottom-plate portion 17extends in the width direction WD so that the thickness directionbecomes the vertical direction VT when the core-wire-holding state ofcore-wire-crimping portion is viewed in the front-rear direction FR.

Each of the pair of core-wire-crimping pieces 19 extends in directions(inward directions in the width direction WD) to approach each other atthe proximal-end portion 23 when the core-wire-holding state ofcore-wire-crimping portion is viewed in the front-rear direction FR.Each of the pair of core-wire-crimping pieces 19 is in contact with eachother at a predetermined location on the central plane in theintermediate portion 25, for example, with a biasing force when thecore-wire-holding state of core-wire-crimping portion is viewed in thefront-rear direction FR. In addition, each of the pair ofcore-wire-crimping pieces 19 extends in directions (directions to beseparated from the central plane or the intermediate portion 25 in thewidth direction WD) to be separated from each other at the distal-endportion 21 when the core-wire-holding state of core-wire-crimpingportion is viewed in the front-rear direction FR.

Furthermore, in order to increase the number of the strands 11 in directcontact with the terminal 5, at least the portion 21B as a part of thedistal-end portion 21 of the core-wire-crimping piece 19 extends in adifferent direction from the other portions 21A and 21C of thedistal-end portion 21 (see FIG. 8) when the core-wire-holding state ofcore-wire-crimping portion is viewed in the front-rear direction FR.

Incidentally, the sheath 9 of the electric wire 3 is held by thesheath-crimping portion 15 by crimping the sheath-crimping portion 15.

Here, the core-wire-crimping portion 13 before being crimpled will bedescribed in detail.

First, a state where the flat plate-shaped material is formed into thepredetermined shape but is not yet subjected to bending will bedescribed. In the state illustrated in FIG. 1, the flat plate-shapedmaterial formed in the predetermined shape is viewed in the thicknessdirection.

The bottom-plate portion 17, the proximal-end portions 23 of the pair ofcore-wire-crimping pieces 19, and the intermediate portions 25 of thepair of core-wire-crimping pieces 19 have rectangular shapes.

In addition, a through hole is not formed in the core-wire-crimpingportion 13 (including the distal-end portion 21) which is configured toinclude the bottom-plate portion 17 and the pair of core-wire-crimpingpieces 19. Thus, considering from the viewpoint of topological geometry,the core-wire-crimping portion 13 can be regarded as the same as asphere when the shape of the core-wire-crimping portion 13 iscontinuously changed.

As illustrated in FIGS. 1, 2, and the like, the distal-end portion 21 ofthe core-wire-crimping piece 19 of the terminal 5 is formed with aplurality of convex portions (protrusions) provided at predeterminedintervals in the longitudinal direction of the electric wire 3.

In other words, the distal-end portion 21 of each of thecore-wire-crimping pieces 19 (19A and 19B) is divided into the pluralityof portions in the front-rear direction FR. More specifically, asillustrated in FIG. 1, the distal-end portion 21 of thecore-wire-crimping piece 19 is formed in a triangular wave shape runningin the front-rear direction FR, that is, formed in a jagged shape,thereby being formed with, for example, the three triangular convexportions 31. At this time, a distal end of the distal-end portion 21 ispointed.

As illustrated in FIGS. 1 to 3, the core-wire-crimping portion 13 of theterminal 5 is configured to include the bottom-plate portion 17 and thepair of core-wire-crimping pieces 19 (19A and 19B) protruding from bothedges of the bottom-plate portion 17 in the width direction WD. The pairof core-wire-crimping pieces 19 (19A and 19B) are bent in the directions(inward) to approach each other at least in the portions 21B of thesedistal-end portions 21.

More specifically, as illustrated in FIG. 3, the bottom-plate portion 17extends in the width direction WD such that the thickness directionbecomes the substantially vertical direction VT, and has an arc shapeprotruding downward when the core-wire-crimping portion 13 is viewed inthe front-rear direction FR.

The proximal-end portion 23, the intermediate portion 25, and theportions 21A and 21C of the distal-end portion 21 of thecore-wire-crimping piece 19A are linearly erected obliquely upward fromone end of the bottom-plate portion 17. The proximal-end portion 23, theintermediate portion 25, and the portions 21A and 21C of the distal-endportion 21 of the core-wire-crimping piece 19B are also linearly erectedobliquely upward from the other end of the bottom-plate portion 17.Incidentally, a distance in the width direction WD between thecore-wire-crimping piece 19A (excluding the portion 21B) and thecore-wire-crimping piece 19B (excluding the portion 21B) graduallyincreases from bottom to top.

The portion 21B of the distal-end portion 21 of the core-wire-crimpingpiece 19A is erected obliquely upward from the distal end (upper end) ofthe intermediate portion 25 of the core-wire-crimping piece 19A. Theportion 21B of the distal-end portion 21 of the core-wire-crimping piece19B is also erected obliquely upward from the distal end (upper end) ofthe intermediate portion 25 of the core-wire-crimping piece 19B.Incidentally, a distance in the width direction WD between the portion21B of the distal-end portion 21 of the core-wire-crimping piece 19A andthe portion 21B of the distal-end portion 21 of the core-wire-crimpingpiece 19B gradually decreases from bottom to top.

Next, the core-wire-holding state of core-wire-crimping portion will bedescribed in detail.

As illustrated in FIGS. 6 to 8, the bottom-plate portion 17 extends inthe width direction WD such that the thickness direction becomes thesubstantially vertical direction VT, and has the arc shape protrudingdownward when the core-wire-crimping portion 13 in the core-wire-holdingstate of core-wire-crimping portion is viewed in the front-reardirection FR.

The proximal-end portion 23 of one of the core-wire-crimping pieces(left core-wire-crimping piece) 19A extends from one end (left end) inthe width direction WD of the bottom-plate portion 17 to the upper rightdirection and then to the lower right direction. That is, theproximal-end portion 23 protrudes in an are shape such as a semicircularshape protruding upward by a first predetermined amount in the rightdirection.

The intermediate portion 25 of the one core-wire-crimping piece 19Aprotrudes downward slightly by a second predetermined amount from thedistal end of the proximal-end portion 23 of the core-wire-crimpingpiece 19A.

The portion 21B of the distal-end portion 21 of the core-wire-crimpingpiece 19A protrudes from the distal end of the intermediate portion 25of the core-wire-crimping piece 19A, by a third predetermined amount, inthe left direction to be an arc shape such as a quarter arc shape asillustrated in FIGS. 6 and 8.

The portions 21A and 21C of the distal-end portion 21 of thecore-wire-crimping piece 19A protrudes from the distal end of theintermediate portion 25 of the core-wire-crimping piece 19A, by a thirdpredetermined amount, in the lower left direction to be an arc shapesuch as a quarter arc shape as illustrated in FIGS. 7 and 8.

In addition, since the core-wire-crimping portion 13 is formed to besymmetric with respect to the central plane, the proximal-end portion23, the intermediate portion 25 and the distal-end portion 21 of theother core-wire-crimping piece (right core-wire-crimping piece) 19B alsoprotrude similarly to the proximal-end portion 23, the intermediateportion 25, and the distal-end portion 21 of the one core-wire-crimpingpiece 19A.

In addition, since the distal-end portions 21 of the core-wire-crimpingpieces 19 protrude in the directions to be separated from each other,and the following configuration is obtained.

The distal-end portion 21 of the one core-wire-crimping piece 19A (theother core-wire-crimping piece 19B) is not in contact with theproximal-end portion 23 and the bottom-plate portion 17 of the onecore-wire-crimping piece 19A (the other core-wire-crimping piece 19B)and protrudes between the proximal-end portion 23 and the bottom-plateportion 17 of the one core-wire-crimping piece 19A (the othercore-wire-crimping piece 19B).

As a result, the portion 21B as a part of the distal-end portion 21 ofthe one core-wire-crimping piece 19A (the other core-wire-crimping piece19B) extends in a different direction from the other portions 21A and21C of the distal-end portion 21.

Incidentally, a value of the first predetermined amount described aboveis larger than a value of the third predetermined amount, for example,the value of the first predetermined amount may be about three times ofthe value of the third predetermined amount. A value of the secondpredetermined amount is small. Therefore, the pair of core-wire-crimpingpieces 19 is in contact with each other in the form of being close toline contact in the intermediate portion 25.

In addition, a length of the core wire 7 exposed after the removal ofthe sheath 9 is slightly longer than a length of the core-wire-crimpingportion 13 in the front-rear direction FR. In the core-wire-holdingstate of core-wire-crimping portion, the core wire 7 slightly protrudesfrom a front end of the core-wire-crimping portion 13, and the core wire7 also slightly protrudes from a rear end of the core-wire-crimpingportion 13. A portion on a further rearward side of the core wire 7slightly protruding at the rear end is covered with the sheath 9, andthis portion of the sheath 9 is held by the sheath-crimping portion 15.

In addition, a tubular portion is formed by the bottom-plate portion 17,and the proximal-end portion 23 and the intermediate portion 25 of thecore-wire-crimping piece 19 in the core-wire-holding state ofcore-wire-crimping portion. Further, the tubular portion surrounds allof the strands 11, that is, the entire circumference of the core wire 7with a biasing force. The distal-end portion 21 of thecore-wire-crimping piece 19 is inserted among the strands 11 by wadingthrough the strands 11 inside the tubular portion with a biasing force.

Next, a connection method between the electric wire 3 and the terminal 5will be described.

First, the sheath 9 is removed such that the core wire 7 is exposed overa predetermined length at a part of the electric wire 3, for example, atone end portion in the longitudinal direction (a sheath removal step).

Subsequently, the core wire 7 exposed by removing the sheath 9 in thesheath removal step is installed onto the core-wire-crimping portion 13(a core wire/terminal installation step).

Simultaneously with the core wire/terminal installation step, a portionof the sheath 9 of the electric wire 3 in the vicinity of the exposedcore wire 7 is installed onto the sheath-crimping portion 15 of theterminal 5 (a sheath/terminal installation step).

After the core wire 7 is installed onto the core-wire-crimping portion13 in the core wire/terminal installation step, the core-wire-crimpingportion 13 is crimped, and the core wire 7 is enclosed and held by thebottom-plate portion 17 and the pair of core-wire-crimping pieces 19 (acore wire holding step).

As a result, the strands 11 with hatching are brought into directcontact with the core-wire-crimping portion 13 as illustrated in FIGS. 6to 8.

Simultaneously with the core wire holding step, the sheath-crimpingportion 15 is also crimped so that the sheath 9 is held by thesheath-crimping portion 15.

According to the electric-wire-terminal-connection structure 1, at leastthe portion 21B as a part of the distal-end portion 21 of thecore-wire-crimping piece 19 extends in a different direction from theother portions 21A and 21C of the distal-end portion 21 of thecore-wire-crimping piece 19. Thus, the number of the strands 11 of thecore wire 7 in direct contact with the core-wire-crimping portion 13 ofthe terminal 5 increases, and the number of the strands 11 of the corewire 7 not in direct contact with the core-wire-crimping portion 13decreases. As a result, an electric resistance between the core wire 7of the electric wire 3 and the terminal 5 can be reduced, and theelectric resistance (at a press-fitting portion) between the core wire 7and the core-wire-crimping portion 13 is stabilized.

In particular, when the strand 11 is made of aluminum or an alloythereof which is likely to form an oxide film on its surface, the oxidefilm on the surface of the strand 11 that is in direct contact with thecore-wire-crimping portion 13 is destroyed by crimping of thecore-wire-crimping portion 13. Then, the core-wire-crimping portion 13and the strand 11 without the oxide film are in direct contact with eachother, and thus, it is possible to reduce the value of the electricresistance between the core wire 7 of the electric wire 3 and theterminal 5.

In addition, the through hole is not formed in the core-wire-crimpingportion 13 including the distal-end portion 21 according to theelectric-wire-terminal-connection structure 1. As a result, the rigidityof the terminal 5 does not decrease, and the increase in the electricresistance caused by the decrease in rigidity is suppressed.

In addition, since the core-wire-crimping portion 13 is formed in thetubular shape to cover the entire outer circumference of the core wire 7of the electric wire 3 according to theelectric-wire-terminal-connection structure 1, the core wire 7 is notexposed in the core-wire-crimping portion 13. As a result, the rigidityof the terminal 5 (particularly the rigidity of the core-wire-crimpingportion 13) does not decrease, and the increase in the electricresistance caused by the decrease in rigidity is suppressed.

In addition, the distal-end portion 21 of the core-wire-crimping piece19 of the terminal 5 is formed with the plurality of convex portions 31(21A, 21B, and 21C) provided at predetermined intervals in thelongitudinal direction of the electric wire 3 according to theelectric-wire-terminal-connection structure 1. As a result, when thecore wire 7 is held by crimping the core-wire-crimping portion 13, thedistal-end portion 21 of the core-wire-crimping piece 19 is easilyinserted inside the core wire 7 (between the large number of strands 11)while wading through the strands 11 without significantly damaging thestrands 11.

In addition, in the terminal 5 before the electric wire 3 is installed,the pair of core-wire-crimping pieces 19 is bent in the directions(inward) to approach each other at the distal-end portions 21 thereofaccording to the electric-wire-terminal-connection structure 1. As aresult, it is unnecessary to form an elongated groove for facilitatingthe bending at a boundary between the distal-end portion 21 and theintermediate portion 25 of the core-wire-crimping piece 19 when crimpingthe core-wire-crimping portion 13 to install the terminal 5 on theelectric wire 3.

Then, the distal-end portion 21 of the core-wire-crimping piece 19 isinserted between the strands 11 of the core wire 7 when crimping thecore-wire-crimping portion 13 to install the terminal 5 on the electricwire 3, and the contact area between the terminal 5 and the core wire 7increases, whereby the electric resistance between the terminal 5 andthe core wire 7 can be reduced.

Meanwhile, the distal-end portion 21 of the core-wire-crimping piece 19is divided into the three portions 21A, 21B, and 21C in the abovedescription, but the distal-end portion 21 of the core-wire-crimpingpiece 19 may be divided into four portions 21A, 21B, 21C, and 21D asillustrated in FIG. 9 or may be divided into five or more portions.

In this case, it is desirable that bending angles of the respectiveportions 21A, 21B, 21C, and 21D be changed as illustrated in FIG. 10.

In addition, the distal-end portion 21 of the core-wire-crimping piece19 is formed in the pointed shape in the triangular shape in the abovedescription. However, the distal-end portion 21 of thecore-wire-crimping piece 19 may be formed with a plurality of portions21A, 21B, and 21C delimited by a plurality of slits 33 provided atpredetermined intervals in the front-rear direction FR as illustrated inFIG. 11.

In addition, the distal-end portion 21 of the core-wire-crimping piece19 may be configured not to be divided into a plurality of portions asillustrated in FIGS. 12 and 13. In this case, when thecore-wire-crimping portion 13 is developed, the bottom-plate portion 17and the pair of core-wire-crimping pieces 19 (the proximal-end portion23, the intermediate portion 25, and the distal-end portion 21) haverectangular flat plate shape.

In addition, in the state before the core-wire-crimping portion 13 ofthe terminal 5 illustrated in FIGS. 12 and 13 is crimped, the distal-endportions 21 (the entire distal-end portion 21) of each of the pair ofcore-wire-crimping pieces 19 are bent inward in the width direction WDsimilarly to the portion 21B of the distal-end portion 21 illustrated inFIG. 3.

Meanwhile, the terminal 5 is installed at the end of the electric wire 3in the longitudinal direction in the above description, but a terminalmay be installed on the core wire 7, exposed by removing the sheath 9,over a predetermined length in an intermediate portion of the electricwire 3 in the longitudinal direction. Incidentally, the terminal in thiscase has a shape different from that of the terminal 5, but is theterminal provided with the core-wire-crimping portion 13.

In addition, the portions (21A, 21B, and 21C) of the distal-end portion21 of the core-wire-crimping piece 19 extend in different directions inthe above description. However, all the portions of the distal-endportion 21 of the one core-wire-crimping piece 19A may extend in thesame direction, or all the portions of the distal-end portion 21 of theother core-wire-crimping piece 19B may extend in the same direction.

That is, an electric-wire-terminal-connection structure may beconfigured to include: an electric wire including a core wireconstituted by a plurality of strands; a terminal including abottom-plate portion and a pair of core-wire-crimping pieces, whichprotrude from both edges of the bottom-plate portion and have distal-endportions each of which is constituted by a plurality of convex portions,the terminal enclosing and holding the core wire by the bottom-plateportion and the pair of core-wire-crimping pieces such that the pair ofcore-wire-crimping pieces extend in directions to approach each other ata proximal-end portion and are in contact with each other at anintermediate portion, and the respective convex portions of thedistal-end portion extend in directions to be separated from each other.

Embodiments of the present invention have been described above. However,the invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

Moreover, the effects described in the embodiments of the presentinvention are only a list of optimum effects achieved by the presentinvention. Hence, the effects of the present invention are not limitedto those described in the embodiment of the present invention.

What is claimed is:
 1. A connection structure between an electric wireand a terminal, the connection structure comprising: an electric wireincluding a core wire with a plurality of strands; and a terminalincluding a bottom-plate portion and a pair of core-wire-crimpingpieces, which protrude from both edges of the bottom-plate portion andeach distal-end portion of the pair of core-wire-crimping pieces beingdivided into a plurality of portions, the terminal enclosing and holdingthe core wire by the bottom-plate portion and the pair ofcore-wire-crimping pieces, wherein the pair of core-wire-crimping piecesextend in directions to approach each other at a proximal-end portion,are in contact with each other at an intermediate portion, and extend indirections to be separated from each other at the distal-end portion,and at least one portion of the plurality of portions of each distal-endportion of the pair of core-wire-crimping pieces extend in a differentdirection from other portions of the distal-end portion.
 2. Theconnection structure between an electric wire and a terminal accordingto claim 1, wherein the distal-end portion of the core-wire-crimpingpiece of the terminal is formed with a plurality of convex portionsprovided at a predetermined interval in the longitudinal direction ofthe electric wire, or the distal-end portion of the core-wire-crimpingpiece is formed with a plurality of portions delimited by a plurality ofslits provided at a predetermined interval in the longitudinal directionof the electric wire.
 3. A terminal comprising: a bottom-plate portion;and a pair of core-wire-crimping pieces protruding from both edges ofthe bottom-plate portion, wherein at least a part of each distal-endportion of the pair of core-wire-crimping pieces are bent in directionsto approach each other.
 4. A terminal comprising: a bottom-plateportion; and a pair of core-wire-crimping pieces protruding from bothedges of the bottom-plate portion and having distal-end portions dividedinto a plurality of portions, wherein at least one portion of theplurality of portions of each distal-end portion of the pair ofcore-wire-crimping pieces extend in a different direction from otherportions of the distal-end portions.
 5. A connection method forconnecting an electric wire and a terminal, the connection methodcomprising: removing a sheath at a part of an electric wire thatincludes a core wire with a plurality of strands and a sheath coveringthe core wire; installing the core wire exposed by removing the sheathonto a core-wire-crimping portion that includes a bottom-plate portionand a pair of core-wire-crimping pieces protruding from both edges ofthe bottom-plate portion and having distal-end portions divided into aplurality of portions such that at least one portion of the plurality ofportions of each distal-end portion extend in a different direction fromother portions of the distal-end portion; and enclosing and holding thecore wire by the bottom-plate portion and the pair of core-wire-crimpingpieces such that the pair of core-wire-crimping pieces extend indirections to approach each other at a proximal-end portion, are incontact with each other at an intermediate portion, and extend indirections to be separated from each other at the distal-end portion,and at least one portion of the plurality of portions of each distal-endportion extend in the different direction from the other portions of thedistal-end portion, after installing the core wire on thecore-wire-crimping portion.
 6. A connection structure between anelectric wire and a terminal, the connection structure comprising: anelectric wire including a core wire with a plurality of strands; aterminal including a bottom-plate portion and a pair ofcore-wire-crimping pieces, which protrude from both edges of thebottom-plate portion and each distal-end portion of the pair ofcore-wire-crimping pieces being formed with a plurality of convexportions, the terminal enclosing and holding the core wire by thebottom-plate portion and the pair of core-wire-crimping pieces, whereinthe pair of core-wire-crimping pieces extends in directions to approacheach other at a proximal-end portion and is in contact with each otherat an intermediate portion, and the respective convex portions of thedistal-end portion extend in directions to be separated from each other.